Compressor



Maf. 3, w25.

J. G. SCOVEL, JR

COMPRESSOR Filed June 16, 1922 2 Sheets-sheet 1 Mar. 3, 1925. 1,528,086

J. c. scovEL; JR t COMPRESSOR Filed June 16, 1922 `2 Sheets-Sheet 2Patented Mar. 3, 1925.

UNITED STATES JOHN o. soo-VEL, Jn., or CHICAGO, ILLINOIS, AGE MFG. co.,OF oIIIcAGO, ILLINOIS,

saumon 'ro THE cnnAMEnY Pa'ox- A CORPORATION OF ILLINOIS.

COMPRESSOR.

.Applicationled J'une 16, 1922. VSerial No. 568,759.

To all whom it may concern Be it known that I, JOHN C. SoovEL, Jr., acitizen of the United States, residing at Chicago, in the count of Cookand the State of Illinois, have Invented certain new and usefulImprovements in Compressors, of which 'the following is a specification.The invention relates to fluid compressors, and more particularly to theconstruction and arrangement of the suc-tion and discharge valves incompressors of the reciprocating piston type. f

It is highly desirable in .compressors of this type, especially ,whenemployed to compress volatile refrigerant gases, that the volumetricefficiency of the machine be high.

l In the more compact machines of comparatively small pistondisplacement and high speed, their efficiency has been limited by thedifficulty of securing sufficient rapidity of action of the valves and asufficient degree of sensitivene s in the latter to variations ofpressure so thatthe full displacement capacity of the piston might beutill pressed gas.

struction 1n ized.. A further limitation in utilizing the displacementcapacity of the piston has occurred with the difficulty of securinglarge valve capacity in a construction which eliminates clearance'between thel piston and cylinder head at the end of the com ressionstroke and completely discharges the com- Also, an objectionable clatterof the valves upon fore attended the operation of such machines at highspeed.

It is one of the objects of the: present invention to provide `acompressor inl which the suction and discharge valves are of largecapacity quickly and fully eective with a minimum of operative movement.

Another object is to provide valves in such a machine which aresensitive to andilmnediat'ely operable by slight differences between thevariable opposing pressures sustained by them in the operation of thepiston.

Another Object is to provide a construction of valve and seat whichminimizes friction in the paing gas, and which maintains a tight seal'`when closed over along period of operative use. A' i y Another object isto provide a valve conthe piston andl in the cylinder their seats hasheretohead *which permits the operation with an inconsiderable amount ofclearance therebetween, and which permits full utilization o-f pistondisplacement capacity together with efficient valve action.

Further objects Include practically noiseless operation; a rigidconstruction of valve members which avoids damage fromdislaced'separable parts; and a simple durale construction of operativeparts permittino ready replacement. Y

ther objects and advantages Willbe apparent in the following detaileddescription of a preferred embodiment of the invention which I havechosen for illustrationin the accompanyingdrawings, and which shows anapplication of -the invention to a comfor use wlth refrIgeratIon pressoradapted apparatus. l

In the drawings, Fig. 1` represents a scc- `tional elevation of acompressor cylinder and piston. Fig. 2 1s an enlarged sectionalelevation of the upper portion of the piston and cylinder, taken on theplane of the line 2-2 in Fig. l and illustrating the structural detailof the valves. Fig. 3 is a cross scctional view as taken on the line 3 3in Fig. 2. Fig. 4 represents a cross sectional view taken on the planeof the linefl-fl in Fig. 2. Fig. 5 is a fragmentary sectional view ofthe discharge valve and seat.

The general organization of the mechanism, as set forth in Fig. 1,comprises a cylinder 1 having a longitudinal bore 2 terminating at itsupper end in an enlarged chamber 3. A removable cover plate 4 cffects aclosure of the chamber 3. 4A water circulating chamber 5 having suitablesupply connections may surround the upper portion of the Walls of thebore 2 to remove the heat ofcomp-ression developed in operation.4

Operatively positioned in the bore 2 is a piston 6 ypreferably of thedouble trunk type comprlsing a bottom part 7 serving as 4a cross-headand an upper part 8 'serving as a compression head. The upper and lowerparts ofthe piston are rigidly \connected,V

'of the bore 2.

vide a large central open space between them, but having clearance fromthe walls Conventional packing or compression rings may be provided inboth heads. The cross head 7 is illustrated as carrying a wrist pin 11and connecting rodl 12 actuated by a conventional power driven crankshaft (not shown) and by which the piston 6 is reciprocated.

rlhe refrigerant gas, or other fluid to be compressed, may be conductedto the cylinder through a pipe 13 opening into a suction chamber 14surrounding the wall of the bore 2, the chamber 14 providing a largesupply of gas tol draw from during the suction stroke of the piston.Preferably several inlet ports 15 open from the upper portion of thechamber 14 into the bore 2 of the cylinder, the ports being .positionedbetween the ranges of travel of the two piston heads so that the gasflows freely into the open space therebetween. The iow of gas from thelatter space during the sucpression head 8 of the tion stroke of thepiston to the compression space above the piston is controlled by asuction valve 16, centrally positioned in the upper wall of the pumpinghead 8, andy described in detail hereinafter.

During the compression stroke of the piston the suction valve 16 isclosed and the gas thereabove is compressed and forced into the highpressure chamber 3 through a discharge valve 17 (to be described indetail hereinafter) preferably carried by a cylinder head 18 lforming anend closure of the cylinder bore 2 and partitioning the compressionspace in the latter from the chamber 3.

The cylinder head 18 is preferably of the safety type resilientlysecured in abut-- ment with the end of the, cylindrical wall of the bore2 bymeans of a compression spring 19 confined between the upper side ofthe cylinder head and the cover plate 4, the spring tension beingsucient to maintain the head 18 inl sealed abutment under normalconditions, but permitting outward movement of the head inl case of anyobstruction between it and the piston due to liquid in the cylinder, abreakage of parts or any other cause, thus preventing extensive damageand the escape of gas in the event of such accident. The compressed smay be led out of the chamber 3 through al port. 20 and discharge pipe21.

Describing now the construction and arrangement of the suction. anddischarge 2. The compiston is provided with an opening through its endwall communicating with the space between the piston heads. lThe endface of the compressionlheadpreferably is recessed to receive a4removable annular plate 22 Hush with the face of the. head and securedthereto as by valves, reference is had to Fig 'means of screws 23.

Adjacent the inner perimeter of the plate 22 a raised annular valve seat24 is provided, preferably integral with the plate. The seat and itssupporting plate may be constructed of material better suited towithstand the wear of the valve action than that of which the piston iscommonly constructed and is readily removable for replacement. Theannular seat 24 isformed with a pyramidal Vmovement within a sleeve 27having radial' arms 28 terminating 1n a ring 29 removably fitted withinan inner recess in the compression head structure below the plate 22.The ring 29 is secured in position by the plate 22, and may bemaintained in snug abutment therewith by means of a resilient member 30,preferably an .annular spring, interposed'lbetween the ring 29 and theshoulder formed at the bottom of its recess. l

A compression spring 31 confined between the arms 28 and the iiange 26normally holds the valve 16 in contact with its seat in closure of thepassage through the compression head. The opening of the valve inoperation is limited by abutment of the flange 26 with the lower end ofthe sleeve 27.

The guide sleeve 27 and its supporting elements are of splitconstruction as illustrated in Fig. 4, in order to permit making thevalve member of ixed construction, in thepresent instance integral,thus'avoiding theuse of lock nuts or other detachable stop means inplace of the flange 26,v such detachable stops being liable to work ofifrom vthe valve stem to the damage of the 'machinel The assembling andreplacement of the valve parts may be facilitated by providing a grooveaboutthe outer periphery of the ring 29 adapted to receive a bindingwire 32 (Fig. 2) to hold the parts of the guide structurein assembledrelation about the valve stem.

lt will be apparent that the large exposed areas and light weight of theplate valve o 16 assures a very sensitive and fast action of the valvebetween the com ression and suction strokes of the piston. T e extremelynarrow width of the valve seat contact surface causes a substantialbalance between vthe surface areas of the valve subjected to opposingpressures when in closed position,

and permits the valvel to open without an excessive dierence inpressures above 'and below the valve. Also, the large perimeter of thevalve opening with its venturi-like radial cross section permits'a veryshort distance of valve liftto give-- free passage to the gas, therebyfurther increasing thel discharge passage .34 is opened centrallythroughthe plate33, the passage preferably being of conical 'peripheral contourof like diameter with that of the suction valve 16, the latter alsohaving a, similar conical periphery.

` pression stroke,

' It will here be apparent that the plate 33 may be positionedimmediately adjacent the position of the piston at'theend of the comsothat with the entry of the valve -16 within the discharge passage 34 thepiston may approach the cylinder head to the ,limit of slight operatingclearance and completely discharge all of the gas from the 'cylinderbore. This arrangement permits the utilization of the full displacement'capacity of the piston, as when any portion of compressed gas remainsin the bore a proportionate part of the suction stroke is ineffectiveuntil the pressure above vthe suction valve is reduced to the point thatthe valve may be opened by the pressure in the suction chamber below. lA discharge .valve seat 35 is provided contignous to the upper edge ofthe passage 34 and preferably integral with the plate 33, the latterbeing recessed on its upper side to N-provide an operating space36 forthe discharge valve 17. The discharge valve 17 is also ofthe flat platetype, and its seat 35 is of pyramidal cross section similar to that ofthe suction valve-seat.

The valve seat construction, as applied in both suction and dischargevalves and illus-. trated in enlarged cross section in, Fig. 5, isespecially advantageous in the discharge valve by reason of the highvvelocity of the compressed gas being forced therethrough and because ofwaste of power which occurs` when there is high frictional resistance tothe passing gas. Efficient valve action at high speed necessitates aminimum of valve lift and a sufficient valve opening to avoid materialresistance to the flowing gas. The cooperating surfaces of the valve andvalve seat, formed in an angular relation approximate to thatillustrated in Fig. 5, give a very high discharge coefficient of theorifice between them, The radial cross section ofl the annular passagebetween the open valve and its seat approximates a venturi, the action,of which is to permit maximum 1ncrease of velocity at the neck of thepassage without materially increasing friction. The

inclined sides of the seat eliminate eddies and their consequentconstriction of the flow of the gas through the orifice, and permit aconsiderable reduction in the valve lift, as compared with the 'usualpoppet and otherV types of valves, without reducing the eRectivecapacity of the valve orifice. The consequent advantageous result isthata -very low' valve lift may be used and a high operative speed maybe efficiently attained without increasing the power 'necessary to drivethe compressor. y

The lseat construction also reduces to a minimum the liability of scalebecoming lodged thereon and preventing a tight closure of the valve. Thewire edged apex of the seat assures a sealing contact at all points with4the valve surface closed upon it.

upper portion of the head 18 and overlies 7- the plate 33, being securedthereto as b v means of bolts38. The guide plate 37 carries a centrallyVpositioned boss or collar 39 defining an axial vpassage 40 extendingthrough the plate 37. The lower end of the passage 40 may be enlarged toform a guide way operatively receiving a guide collar 41 fixedvcentrally upon the discharge valve 17. A compression spring 42,preferably positioned within the passage 40 between the valve 17 and apreferably removable end .The removable construction of the valveclosure or plug 43 secured in the collar 39,

tends to lio-ld lt-he valve 17 in contact with its seat. A series ofholes 44 opening through the guide plate 37 into the valve operatingspace affords passage for the gas flowing through the discharge valveinto the chamber 3.

The position of the holes 44 in relation to lthe discharge valve 17 isimportant in that, .by approximately centering the holes ovei' the edgeof the valve, eddy currents are y produced therein which react upon thcupper surface of the open valve to partially counter balance thepressure below. thus increasing the rapidity with which the valvewillclose upon completion of the compression stroke of the piston. Thisaction occurs only when the gas is flowing through the open valve, anddoes not add resistance to the operative movement of the valve from itsseat in opening.

An annular ring 45 of fibre or other suitable material maybe secured asby rivets 46 to .the under side. of the guide plate 37 above the valve17, thus providin a slightly resilient stop limiting the upwar movementof the valve and further reducing the noise lcommonly attending theoperation of the discharge vvalves in compressors.

tThe' collar 39 also serves as a positioning retainer for the safetyhead compression lspring 19 bearing thereabout upon the late 37 andnormally securing the cylinder ead assembly in vsealed abutment with theend wall of the,y cylinder bore 2.

It will nowv be apparent that I have pro vided a compressor having animproved valve arrangement which embodies superior advantages inoperation, and which is of simple durable construction.

I claim as my invention:

1. A fluid compressor comprising a cylinder, a piston head thereinhaving a lon' itudinal passage, a shoulder formed in t e passage, aplate removably secured to the' end of said head having anoriliceopening into said passage, said plate forming a valven seat, aring in said passage removably secured between said plate and saidshoulder,

a resilient annulus interposed between said ring and said shoulder, anda valve lsupported by said ring in cooperative relation to said valveseat to control said passage.

2. A fluid compressor comprising a cylinder, a piston head thereinhaving a longitudinal passage, a shoulder formed in the passage, a plateremovably secured to the end of said head having an orifice opening intosaid passage, said plate forming a valve seat, a ring in said passageremovably secured between said plate and said shoulder, and a valvesupported by said ring in cooperative relation to said valve seat tocontrol said passage.

3. In a fluid compressor, a piston head having a passage therethrough, ashoulder formed in the passage, a plate removably secured to the end ofsaid head having an orifice opening into said passage, a valve seatformed on said plate about said orifice, a valve co-operating with saidseat to control said passage and having a guide stem, a flange fixed onthe end of said stem, a

sleeve operatively supporting said stem and limiting its longitudinalmovement in one direction by abutment with said flange, a ring in saidpassage removably' secured between said plate and said shoulder, spacedsupporting members rigidly connecting said Y sleeve and said ring toform a unitary structure, said structure being divided through saidsleeve into parts separable to receive said stem, and a binding elementpositioned having an orifice opening from said recess' into said bore,said plate having an integral valve seat formed at the bottom of saidrecess about said orifice, a second plate overlying and removablysecured to said first mentioned plate having a circular series 'ofpassages therethrough communicating with said recess and said chamber,an upwardly extending annular boss integrally formed on said secondmentioned plate having an inner guide bearing opening into said recesscentrally of said passages, a valve in said recess adapted to co-operatewith said seat to control said orifice and having a guide collaroperably positioned in said guide bearing, the lateral periphery of saidvalve extending beneath said passages in substan-l tially centeredrelation thereto, resilient means wit-hin said annular boss tendingnormally to hold said valve in contact with its seat, and a stop ofresilient material secured to saidl second mentioned plate in positionto limit the movement of said valve from its seat.

5. In a fluid compressor having a cylinder with its bore terminating inan enlarged chamber, a head in said chamber effecting an end closure ofthe bore and comprising, a plate abutting the end of the wall of saidbore having a recess in its outer face and having an orifice openingfrom saidlrecess into said bore, said plate having a valve seat formedat the bottom .of said recess about said orifice, a second plateoverlying and removably secured to said first mentioned plate. having -acircular series of pas- Sages therethrough communicating with saidrecess and sald chamber, a guide bearing in said second mentioned platepositioned centrally of said passages, a valve in said recess adapted toco-operate with said seat to control said orifice. and having aguidemember operatively positioned in said guide bearing, the lateralperiphery of said valve extending beneath said passages in substantiallycentered relation thereto, and resilient'means normallyT tending toretain sa1d valve 1n contact with sald seat. In witness whereof I havehereunto set my hand.

, JOHN C. SCOVEL, JR.

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